This invention relates to alkali metal N-methylaminobutyrates. In one of its aspects this invention relates to a continuous process for making alkali metal N-methylaminobutyrate. In still another aspect of this invention it relates to the preparation of dehydrated slurries of alkali metal N-methylaminobutyrate. In still another aspect of the invention it relates to the preparation of complexes of alkali metal N-methylaminobutyrate and alkali metal bisulfide.
Alkali metal N-methylaminobutyrates are useful as reactants in the preparation of poly(arylene sulfide). The most commonly used of the alkali metal N-methylaminobutyrates is sodium N-methylaminobutyrate (SMAB). Often, SMAB or other alkali metal N-methylaminobutyrates are prepared in situ in a reaction vessel to which a sulfur source and polyhalo substituted aromatic compounds are later added.
It has now been found that this valuable chemical intermediate can be produced continuously for use in a continuous process for making poly(arylene sulfide) or for storage or shipment for such a process. It has been further found that not only the alkali metal N-methylaminobutyrate can be made continuously, but also that complexes of this material with alkali metal bisulfide can be made continuously. The continuous preparation of this latter type of compound is particularly advantageous for use in the preparation of poly(arylene sulfide).
It is, therefore, an object of this invention to provide alkali metal N-methylaminobutyrate and alkali metal N-methylaminobutyrate-alkali metal bisulfide complex compositions which can be used as reactants in poly(arylene sulfide) production. It is also an object of this invention to provide a continuous process for the preparation of alkali metal N-methylaminobutyrate and complexes of this material and alkali metal bisulfide. It is still another object of this invention to provide a process for further treating alkali metal N-methylaminobutyrate and complexes of this material with alkali metal bisulfide to dehydrate the reaction mixture producing a product from which the water has been substantially removed. It is another object of this invention to provide a slurry of alkali metal N-methylaminobutyrate or a slurry of alkali metal N-methylaminobutyrate complexed with alkali metal bisulfide in N-methylpyrrolidone that is suitable for immediate use, shipping, or storage.
Other aspects, objects and the various advantages of this invention will become apparent upon reading this specification in conjunction with the drawing and the appended claims.